That's not something in SOS Battles, but I could try and cook up a patch?
Looking at it, I'll talk to Lucidious about it, but I am not sure.
Can you send the exact error you got?
This is the error:
[2022-10-07 22:35:42 -0400]
[Pokémon Essentials version 20.1]
[v20.1 Hotfixes 1.0.4]
Exception: NoMethodError
Message: undefined method `pokemon=' for nil:NilClass
Backtrace:
[Enhanced UI] [001] Enhanced UI.rb:316:in `block in pbUpdateTargetIcons'
[Enhanced UI] [001] Enhanced UI.rb:313:in `each'
[Enhanced UI] [001] Enhanced UI.rb:313:in `pbUpdateTargetIcons'
[Essentials Deluxe] Fight Menu.rb:291:in `pbHideMoveInfo'
[Essentials Deluxe] Fight Menu.rb:380:in `block in pbFightMenu'
[Essentials Deluxe] Fight Menu.rb:324:in `loop'
[Essentials Deluxe] Fight Menu.rb:324:in `pbFightMenu'
[Essentials Deluxe] Fight Menu.rb:219:in `pbFightMenu'
155:Battle_CommandPhase:222:in `block (2 levels) in pbCommandPhaseLoop'
155:Battle_CommandPhase:213:in `loop'
=================
Edit: just edited the enhanced UI plugin to skip stuff under pbUpdateTargetIcons if the no SOS battle switch is off as a temporary fix.